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RGB Pixel Brightness Characteristics of Linked Color Imaging in Early Gastric Cancer: A Pilot Study

Sun X1, Zhao L2

Gastroenterol Res Pract. 2020 Mar 31;2020:2105874. doi: 10.1155/2020/2105874. eCollection 2020.

Background and aims: Linked color imaging (LCI) helps screen and diagnose for early gastric cancer by color contrast in different mucosa. RGB (red, green, and blue) pixel brightness quantifies colors, which is relatively objective. Limited studies have combined LCI images with RGB to help screen for early gastric cancer (EGC). We aimed to evaluate the RGB pixel brightness characteristics of EGC and noncancer areas in LCI images.

Methods: We retrospectively reviewed early gastric cancer (EGC) patients and LCI images. All pictures were evaluated by at least two endoscopic physicians. RGB pixel brightness analysis of LCI images was performed in MATLAB software to compare the cancer with noncancer areas. Receiver operating characteristic (ROC) curve was analyzed for sensitivity, specificity, cut-off, and area under the curve (AUC).

Results: Overall, 38 early gastric cancer patients were enrolled with 38 LCI images. Pixel brightness of red, green, and blue in cancer was remarkably higher than those in noncancer areas (190.24 ± 37.10 vs. 160.00 ± 40.35, p < 0.001; 117.96 ± 33.91 vs. 105.33 ± 30.01, p = 0.039; 114.36 ± 34.88 vs. 90.93 ± 30.14, p < 0.001, respectively). Helicobacter plyori (Hp) infection was not relevant to RGB distribution of EGC. Whether the score of Kyoto Classification of Gastritis (KCG) is ≥4 or <4, the pixel brightness of red, green, and blue was not disturbed in both cancer and noncancer (p > 0.05). Receiver operating characteristic (ROC) curve for differentiating cancer from noncancer was calculated. The maximum area under the curve (AUC) was 0.767 in B/G, with a sensitivity of 0.605, a specificity of 0.921, and a cut-off of 0.97.

Conclusions: RGB pixel brightness was useful and more objective in distinguishing early gastric cancer for LCI images.

1 VIP Department and General Medicine Department, Beijing Hospital, National Center of Gerontology, Institute of Geriatric Medicine, Chinese Academy of Medical Sciences, China 100730
2 Department of Gastroenterology, Beijing Hospital, National Center of Gerontology, Institute of Geriatric Medicine, Chinese Academy of Medical Sciences, China 100730

Clinical Validation of BASIC Classification for the Resect and Discard Strategy for Diminutive Colorectal Polyps

Rondonotti E1, Hassan C2, Andrealli A1, Paggi S1, Amato A1, Scaramella L1,3, Repici A4, Radaelli F3.

Clin Gastroenterol Hepatol. 2020 Jan 7. pii: S1542-3565(20)30001-X. doi: 10.1016/j.cgh.2019.12.028. [Epub ahead of print]

Background and Aims: Blue-light imaging (BLI) is a chromoendoscopy technique that uses direct (not filtered) emission of blue light with short wavelength (410 nm) to increase visibility of microvascular pattern and superficial mucosa. A BLI-based classification system for colorectal polyps (also called BLI Adenomas Serrated International Classification, BASIC) has been created and was validated using still images or short videos. We aimed to validate BASIC in a clinical practice setting, using thresholds recommended by the American Society for Gastrointestinal Endoscopy for the resect and discard strategy as the reference standard.

Methods: We studied 333 patients (mean age, 62.7±8.1 y; 176 men) who underwent screening colonoscopy from January through July 2019. Six endoscopists trained in BASIC participated in the study. All detected diminutive polyps were characterized by real-time BLI and categorized as adenoma or non-adenoma according to BASIC. All polyps were removed and evaluated by histopathology. The BLI-directed surveillance intervals (based on high-confidence characterization of polyps 5 mm or smaller and pathology feature for others) were compared with histology-directed surveillance intervals, according to United States Multi-society Task Force and European Society of Gastrointestinal Endoscopy recommendations. We calculated negative-predictive values of optical real-time analysis of diminutive rectosigmoid adenomas.

Results: When we applied BASIC, 748 polyps smaller than 5 mm were categorized with 89% accuracy (95% CI, 85.9%-90.6%). BLI-directed surveillance was correct for 90% of patients according to the United States Multi-society task force criteria (95% CI, 86%-93%) and for 96% of patients according to European Society of Gastrointestinal Endoscopy criteria (95% CI, 93%-97%). The negative-predictive value for 302 polyps smaller than 5 mm, located in the rectosigmoid colon and evaluated with high confidence, based on histologic features of adenomatous polyps, was 91% (95% CI, 85%-95%).

Conclusions: Our analysis of data from 333 patients undergoing screen colonoscopies supports the validity of BASIC discriminating diminutive colorectal polyps with histologic features of adenomas from non-adenomas. This allows for the implementation of the resect and discard strategy based on BLI in clinical practice. ClinicalTrials.gov no: NCT03746171.

1 Gastroenterology Unit, Valduce Hospital, Como, Italy
2 Digestive Endoscopy, Nuovo Regina Margherita Hospital, Rome, ltaly
3 Dipartimento di Fisiopatologia Medico-Chirurgica e dei Trapianti, Universita degli Studi di Milano, Milano, Italy
4 Digestive Endoscopy Unit, Division of Gastroenterology, Humanitas Clinical and Research Center and Humanitas University, Rozzano, Italy

Significance of Linked Color Imaging for Predicting the Risk of Clinical Relapse in Ulcerative Colitis.

Kanmura S1, Tanaka A1, Yutsudou K1, Kuwazuru K1, Komaki F1, Komaki Y1, Iwaya H1, Arima S1, Sasaki F1, Tanoue S1, Hashimoto S1, Ido A1.

Gastroenterol Res Pract. 2020 Mar 6;2020:3108690. doi: 10.1155/2020/3108690. eCollection 2020.

Ulcerative colitis (UC) is a chronic inflammatory bowel disease with unknown etiology. Recently, mucosal healing has emerged as an important therapeutic endpoint in UC. Linked color imaging (LCI) is a novel endoscopic system that enhances the color differences of the gastrointestinal mucosa. Our previous study emphasized the redness and yellowness of the lesion using LCI observation, which was useful for the evaluation of histological mucosal activity in UC. In this study, we aimed to evaluate the correlation between LCI observation and clinical relapse rate in UC patients. We retrospectively analyzed UC patients who underwent total colonoscopy between August 2016 and October 2018 at our facility with Mayo endoscopic scores of 0 or 1. We assessed the correlation between orange-like color lesion (defined as LCI-scarlet color lesions) and clinical relapse rate (requiring additional treatment for UC) during the 1-year follow-up period. Fifty-eight patients (22 female, 36 male; median age at diagnosis, 47.2 (18-80) years) who underwent colonoscopy were analyzed. During the 1-year follow-up period, clinical relapse was observed in 12 patients (20.1%) among which ten patients (83.3%) had an LCI-scarlet color lesions recognized by LCI. By contrast, 29 patients (63%) had no LCI-scarlet color lesions in the clinical remission group (n = 46). There was a significant difference in LCI-scarlet color between the clinical relapse and remission groups, remaining significantly associated with clinical relapse. LCI findings, including an orange-like color lesion, have diagnostic implications for predicting the risk of clinical relapse in UC during the 1-year follow-up period.

1 Digestive and Lifestyle Diseases, Kagoshima University Graduate School of Medical and Dental Sciences, Kagoshima, Japan

Linked Color Imaging of Eosinophilic Esophagitis.

Abe Y1,2, Sasaki Y1, Kon T1, Ueno Y1.

Intern Med. 2020 Mar 19. doi: 10.2169/internalmedicine.4381-19. [Epub ahead of print]

A 74-year-old man with dysphagia underwent screening endoscopy. Characteristic endoscopic findings of eosinophilic esophagitis (EoE), such as furrows, rings, or exudates, were not clearly observed, but edematous mucosa was vaguely detected on white light imaging (Picture 1a). These areas were highlighted as a beige color area on blue laser imaging (BLI) (Picture 1b) and a yellowish area on linked color imaging (LCI) (Picture 1c and 1d). Intense eosinophilic infiltration was observed in these image-enhanced areas histologically, but no similar observation was made in
the normal-appearing mucosa (Picture 2a, 2b). This patient was ultimately diagnosed with EoE. A meta-analysis reported that 15% of adult patients have no characteristic endoscopic manifestations of EoE (1). BLI and LCI are newly developed endoscopic imaging technologies on which the visibility of various organic lesions, such as inflammation or tumors, is enhanced (2). These technologies may improve the diagnostic accuracy of EoE by increasing the visibility of esophageal eosinophilia.

1 Department of Gastroenterology, Yamagata University Faculty of Medicine, Japan
2 Division of Endoscopy, Yamagata University Hospital, Japan

The efficacy of tumor characterization and tumor detectability of linked color imaging and blue laser imaging with an LED endoscope compared to a LASER endoscope

Naohisa Yoshida 1, Osamu Dohi 1, Ken Inoue 1, Satoshi Sugino 1, Ritsu Yasuda 1, Ryohei Hirose 1, Yuji Naito 1, Yutaka Inada 2, Takaaki Murakami 3, Kiyoshi Ogiso 4, Yukiko Morinaga 5, Mitsuo Kishimoto 5, Yoshito Itoh 1

International Journal of Colorectal Disease 2020 Feb 22[Online ahead of print]

Objectives: An endoscope with a light-emitting diode (LED) light source which has a 2-mm close-distance observation function without magnification, has been marketed, enabling linked color imaging (LCI) and blue laser imaging (BLI) for tumor detection and characterization. We analyzed the efficacy of a LED endoscope compared to a LASER endoscope.

Methods: We retrospectively reviewed 272 lesions observed using the LED endoscopic system (Fujifilm Co., Tokyo, Japan) from May 2018 to September 2019. The Japanese NBI Classification was used for tumor characterization. We analyzed the diagnostic accuracy and confidence level. Sixty-one lesions observed with both the LED and magnified LASER endoscopes were also analyzed to compare the diagnostic accuracy. Regarding the tumor detectability, we calculated color difference values (CDVs) and brightness values (BVs) of white-light imaging, BLI, and LCI modes between the two endoscopes for each tumor.

Results: The mean polyp size was 9.2 ± 11.3 mm. Histology showed 71 sessile serrated lesions, 193 adenoma and high-grade dysplasias, and 8 T1 cancers. The diagnostic accuracy of tumors ≥ 10 and < 10 mm was 72.0% and 92.9% (p < 0.001), respectively and the high confidence rate was 93.8%. The diagnostic accuracy of LED (77.0%) was a little higher than that of LASER without magnification (65.6%, p = 0.16) but was not inferior to that of LASER with magnification (82.0%, p = 0.50). The respective CDVs of LED and LASER endoscopes were 20.6 ± 11.2 and 21.6 ± 11.2 for LCI (p = 0.30), and the respective BVs were 210.0 ± 24.2 and 175.9 ± 21.1 (p < 0.001).

Conclusions: A LED endoscope with close-distance observation improved tumor detection and characterization due to high brightness.

1 Department of Molecular Gastroenterology and Hepatology, Graduate School of Medical Science, Kyoto Prefectural University of Medicine, Kyoto, Japan
2 Department of Gastroenterology, Fukuchiyama City Hospital, Kyoto, Japan
3 Department of Gastroenterology, JCHO Kyoto Kuramaguchi Medical Center, Kyoto, Japan
4 Department of Gastroenterology, Osaka General Hospital of West Japan Railway Company, Osaka, Japan
5 Department of Surgical Pathology, Graduate School of Medical Science, Kyoto Prefectural University of Medicine, Kyoto, Japan

Usefulness of cold polypectomy under linked color imaging.

Suzuki T1, Kitagawa Y1, Nankinzan R1, Yamaguchi T2.

Endosc Int Open. 2020 Jan;8(1):E87-E91. doi: 10.1055/a-1035-9411. Epub 2020 Jan 8.

Background and study aims: Cold polypectomy is becoming popular for treatment of colon polyps due to its safety and convenience, but there is still the problem of tumor remnants. Because linked color imaging (LCI) improves polyp visibility, cold polypectomy under LCI is anticipated to reduce the tumor remnant rate. Therefore, we investigated the usefulness of this procedure.

Patients and methods: Fifty patients scheduled to undergo cold polypectomy for treatment of colon polyps < 10 mm and assumed to be adenomas were registered prospectively. After performing cold snare polypectomy (CSP) under LCI, biopsy was performed at two resection margin sites for each polyp to determine the tumor remnant rate.

Results: A total of 145 lesions were treated by CSP. Of the 139 lesions in which polyps were retrievable and diagnosed as adenomas pathologically, one lesion was recognized as a remnant adenoma on biopsy (remnant rate: 0.7 % [95 % CI: 0.0-4.4]). This remnant rate was extremely low. Treatment results were extremely promising given that en bloc resection, post-procedure bleeding, and perforation rates were 100 %, 0 %, and 0 %, respectively.

Conclusion:  Cold snare polypectomy under LCI may be an effective treatment method capable of reducing the tumor remnant rate. This trial was approved by our Institutional Ethics Committee and registered at the University Hospital Medical Information Network (UMIN 000033690).

1 Department of Endoscopy, Chiba Cancer Center, Chiba, Japan
2 Department of Gastroenterology, Chiba Cancer Center, Chiba, Japan